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Conservation of energy

  • Thread starter Kuklinski
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  • #1
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I don't know if I'm setting up the energies correctly.

1. Two objects are connected by a light string passing over a light, frictionless pulley. The object of mass m1=5.00kg is released from rest at a height h=4m above the table. Using the isolated system model, (a) determine the speed of the object of mass m2=3.00kg just as the 5.00-kg object hits the table and (b) find the maximum height above the table which the 3.00-kg object rises.



2. E1=Ef
KE=.5mv2
U=mgh




3. Ei=Ef
m1gh=m2gh + .5(m1+m2)v2
5(9.8)(4) = 3(9.8)(4) + .5(8)(v2
v=4.43m/s
 

Answers and Replies

  • #2
tiny-tim
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Welcome to PF!

Hi Kuklinski! Welcome to PF! :smile:
Two objects are connected by a light string passing over a light, frictionless pulley. The object of mass m1=5.00kg is released from rest at a height h=4m above the table. Using the isolated system model, (a) determine the speed of the object of mass m2=3.00kg just as the 5.00-kg object hits the table and (b) find the maximum height above the table which the 3.00-kg object rises.

Ei=Ef
m1gh=m2gh + .5(m1+m2)v2
5(9.8)(4) = 3(9.8)(4) + .5(8)(v2
v=4.43m/s
Yes, that looks fine. :smile:

What's worrying you about it? :confused:
 

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